Siobhan Magnus and Doubtful Guest perform "Far Behind" by Candlebox

Siobhan Magnus and Doubtful Guest perform "Far Behind" by Candlebox, Live in Nashville.

Siobhan Magnus and Doubtful Guest perform "Semi-Charmed Life" by Third Eye Blind

Siobhan Magnus and Doubtful Guest perform "Semi-Charmed Life" by Third Eye Blind, Live in Nashville.

Siobhan Magnus performs Radiohead's "High and Dry" Live

Siobhan nails the Radiohead classic "High and Dry". From the Some Sunny Songs from the Salty Side show on Cape Cod.

Siobhan Magnus and Brendan Princi sing "Fire on the Mountain" Live

Siobhan Magnus and Brendan Princi perform The Grateful Dead's "Fire on the Mountain" Live from the Some Sunny Songs from the Salty Side show at the Cotuit Center for the Arts on Cape Cod.

Siobhan Magnus performs "Piece Of My Heart" by Janis Joplin

The Ultrasonic Rock Orchestra featuring Siobhan Magnus performs Janis Joplin's "Piece Of My Heart"

Siobhan Magnus - Black Doll (Official Video)

Siobhan Magnus - Black Doll (Official Video) from her album Moonbaby.

Siobhan Magnus performs The Beatles' "While My Guitar Gently Weeps"

Ultrasonic Rock Orchestra featuring Siobhan Magnus performs "While My Guitar Gently Weeps" by The Beatles

Siobhan Magnus performs Queen's "Somebody To Love"

The Ultrasonic Rock Orchestra featuring Siobhan Magnus performs "Somebody To Love" by Queen.

Siobhan Magnus pre-American Idol video with band Lunar Valve

On today's CapeCast: See exclusive video of American Idol Season 9 finalist Siobhan Magnus during her rock years on Cape Cod - playing with her band Lunar Valve.

American Idol's Siobhan Magnus sings “I’d Love to Change The World”

American Idol Season 9's Siobhan Magnus sings Ten Years After's “I’d Love to Change The World”

Siobhan Magnus sings "Ball N Chain"

American Idol Season 9 Top 6 finalist Siobhan Magnus sings "Ball N Chain" with her band, Lunar Valve.

Siobhan Magnus, the Idolatry interview (part 1)

American Idol Season 9's Siobhan Magnus sits down with Michael Slezak for the Idolatry interview: The Glassblower part 1 - Wicked Raincoat Theri.

Siobhan Magnus: The Harry's session (vol. 2: Siobhan rocks Harry's Bar)

CapeCast turns back the rock clock to 2009, when American Idol finalist Siobhan Magnus hit the stage at Harry's bar in Hyannis -- see what she sounded like then!

Siobhan's back on Cape Cod/CapeCast: The Siobhan Magnus Interview

On today's CapeCast: We catch up with "American Idol" superstar Siobhan Magnus in Hyannis for a lovely chat about singing and riding the crazy train called fame!

American Idol Siobhan Magnus performs "Poor Wandering One"

American Idol Season 9 contestant Siobhan Magnus performs a song called "Poor Wandering One" from a Fall 2006 production of "The Pirates of Penzance" by the Barnstable High School Drama Club.

Siobhan Magnus sings "Paint it Black" on the Idols Live Tour!

American Idol Season 9's Siobhan Magnus sings The Rolling Stones'"Paint it Black" on the Idols Live Tour!

Siobhan Magnus Performs "Stockholm Syndrome" Live During Her Hometown Visit

American Idol Season 9's Siobhan Magnus performs "Stockholm Syndrome" by Muse live during the hometown visit of the Idols LIVE tour!

Siobhan Magnus sings "Stockholm Syndrome" Live on the Idols Live Tour

American Idol Season 9's Siobhan Magnus performs "Stockholm Syndrome" by Muse Live! in Atlanta on the Idols LIVE tour!

Siobhan Magnus sings “Wicked Game” by Chris Isaak on American Idol

Siobhan Magnus sings “Wicked Game” by Chris Isaak on the American Idol Season 9 Top 24 show.

American Idol Siobhan Magnus singing "Living for the City"

American Idol Season 9 contestant Siobhan Magnus singing Stevie Wonder's "Living for the City" on Hollywood Week Day 3